Safety mechanism for rubber-mixing machines



F. H. BANBURY Filed Feb. 14 1924 @et 2E '1924-- SAFETY MECHANISM Fon RUBBER MIXING MACHINES Patented @et 21, 1924.

STATES EY H. BANBURY, F ANSONIA,ACONNECTICUTI, ASSIGNOR T0 BIRMINGHAM RON FOUNDRY, 0F DERBY, CONNEC'IIICUT, A CORPORATION 0F CONNECTICUT.

SAFETY MECHANISM FOR RUBBER-MIXING MCHINES.

Application led February 14, 1924. Serial No. 692,687.

To all whom it may concern:

Be it known that I, Fnnnmr' H. BAN- BURY, a citizen of the United States, residing at Ansonia, in the count of New Haven and 'State of Connecticut, ave invented a new and useful Improvement in Safety Mechanism for Rubber-Mixing Machines,

of which the following is a specification.

' This, inventionrelates more especially to machines for treating pl-astic material, such as rubber, of the type that have a casing containing a chamber in which are one or more rotors designed when rotated to break up, crush, knead and masticate the stock that is fed into the chamber as described in Patent #1,200,070, dated ctober 3, 1916. In machines of this class there is a vertically movable weight located in a neck above the rotor casing which weight is lowered down upon the stock being treated and allowed to work up and down as the material is being agitated, as set forth in Patent #1,- 370,398, dated March 1, 1921. This weight is connected with a piston in a cylinder above the neck which piston is designed to be raised by air pressure in order that the weight may be lifted to so free the hop-per door past which the weight travels, that material may be fed through lthe door into the mixing chamber. After the door is closed the air pressure is relieved and the weight permitted to descend and float upon the material while it is being manipulated by the rotors. It is desirable that the hopper door should lbe closed or nearly closed efore it is possible for the weight to be lowered in order to eliminate the liability of accident to the operative of the machine, such for instance, as the failure of the air, which would allow the weight to drop suddenly while repairs were being made, or the operative is cleaning out the casing, or attempting to feed in and clear the hopper of stock by pushing it into the casing with his hands.

The object of the present invention is to rovide a machine of the character descri d with safety means whereby the wei ht cannot drop or be lowered until the 5@ feed door is closed or nearly closed, and thus obviate the liability of injury to an employ.

This obect is attained by arranging a safety cate in such manner that it will pro j ect into the casing in the path of the weight -is movable up an and hold it up while the feed door is open, the catch being positively connected with the door by such means that closing the door withdraws the ,catch and opening the door forces the catch into the casing beneath the weight. l

In the accompanying drawings Fig. 1 shows a section of a plastic treating ma chine with a safety `mechanism indicated in dotted outline in the position which it takes when the hopper door is closed. Fig. 2 shows the safety mechanism with the parts in .the position occupied when the door is open. ig. 3 shows an edge view of the safety mechanism in locking position. Fig. 4 is an edge view with the safety mechanism in unlocked position.

In the machine illustrated there are two rotors 1 of well known form rotatably mounted in a chamber 2 in the casing 3. The rotorsr are shown as hollow in order that they may be water-cooled and the cas ing is also chambered for the same At the bottom of the chamber is a discharge door 4. The stock toi be treated is fed into the rotor chamber through a neck 5 from the hopper 6 when the door 7 that closes the opening from the hopper to the neck, is open. The lower edge of the door is fastened to the hinge pin 8. The wei ht 9 is fitted to move vertically in the nec opposite the hopper door opening. A rod 10 connects the wei ht with a iston 11 that down in the cylinder 12. The usual connections are made for admitting air pressure to the cylinder vbelow thel piston for lifting the weight. After the chamber has been charged the hopper door is closed and the wei ht allowed to descend upon the stock and oat thereon while thev stock is being agitated by the rotors.

Extending through the side wall into the neck Vbelow the welght when the weight is in its highest position is a pin 13. This pin is rotatable and slidable 1n and out in a boss 14, and it is preferred to rovide the pin with a spiral slot 15 and drive a dowel pin 16 through the hub into this slot so that when the pin is rotated in one direction it will be forced inward and when it is rotated in the opposite direction it will be drawn outward. Fastened to the outer end of the pin is a rocker arm 17 and this rocker arm is connected by a link 18 with the end of a lever 19 which is fastened to l one end of the hinge pin to which the hopper door is secured.

f, With this mechanism when the door is moved from its closed position, shown in Fig. 1, to open position, illustrated by dotted' lines in Fig. 2, the lever through the vlink and rocker arm turns the lock pm and causes it to be forced inward so that its inner end will project beneath the weight. With the pin in this position the weight cannot descend even should the air pressure beneath the piston in the cylinder fail. When the door is moved from open position, illustrated in Fig. 2, to closed position, shown in Fig. 1, the lever through the link and rocker arm rotates the pin in such direction that when the door is shut 'or nearly Vshut the pin will be withdrawn from beneath the weight, leaving the weight free to be lowered. By positively connecting the locking pin with the door and causingnt to move synchronously therewith the weight is prevented from dropping when the door is opened and can only drop when the door is closed, or nearly closed, thus eliminating the possibility of an operative who should be repairing, cleaning, or feeding stock into the machine, becoming injured by any accidental dropping of the weight. l

Meansequivalent to those described for connecting the door withr the locking pin f or moving the pin in andv out synchronously with the o enin and closing of the door, such as wil rea ily suggest themselves to those skilled in the art, may be employed without departing from the invention.

The invention claimed is 1. In a machine of the character set' forth for treating plastic material, adoor adapted tw be o ened to permit the feeding fy material into the machine, a weight adapted to float upon the material being treated, means for lifting the weight, means for locking the weight in its elevated position, and mechanism connecting said locking means with the door whereby said means `is caused to positively lock the weight in its raised position when the door is open andl locking the weight in its elevated position,

and mechanism connecting said locking means with the door whereby said means 1s caused to positively lock the weight in its raised position when the door is open and unlock the weight so that it may be lowered when the door is closed.

3. In a machine of the character set forth for treating plastic material, a door adapted to be opened to permit the feeding of material into the machine, a weight ada ted to be raised and lowered past said means for lifting the weight, a pin adapted to engage the weight in its elevated position, and mechanism connecting said pin with the Vdoor whereby said pin is caused to be enf oor,

gaged with the weight in its raised position by the opening of the door and disengaged from the weight by the closing of the door.

4. In a machine of the character set forth for treating plastic material, a door adapted to be opened to permit the feeding of material into'the machine, a weight ada ted` to be raised and lowered past said oor, means for lifting the weight, a-rotatable and longitudinally movable pin, and mechanism connecting said pin with the door whereby the opening movement of the door causes the -rotation and projection of the in into the path of the weight and the closing of the door causes the rotation and withdrawal of the pin from the path of the 

